1. Field of the Invention
The present invention relates generally to semiconductor devices that include fine pitch arrays and, more specifically, semiconductor devices that include contacts that are arranged to facilitate an increase in density and a decrease in pitch of such arrays, as well as an effective decrease in pitch of contacts of such arrays. More specifically, the present invention relates to semiconductor devices with staggered contacts.
2. Background of Related Art
The dimensions of many features of semiconductor devices are ever-decreasing to facilitate increases in feature, or device, densities. Each time another decrease in feature dimensions is accomplished, a variety of challenges have been overcome.
A current challenge in decreasing device dimensions has been presented by the fabrication of conductive structures, referred to in the art as “contacts,” that are used to establish conductive links between bit lines and corresponding conductively doped active-device regions in a semiconductor substrate. Due to limitations in the height-aspect ratios that may be achieved by state-of-the-art etch processes, contact holes having sufficient dimensions at the bases thereof cannot be formed. As a result, contact holes are formed in two or more process steps. Initially, a base portion of each contact hole is fabricated in a base layer of dielectric material. The base of the contact hole is filled with conductive material, which forms a so-called conductive “plug” in the contact hole, which is in electrical communication with the underlying active-device region. One or more upper layers of dielectric material are then formed over the base layer of dielectric material and the conductive plugs that extend therethrough. An upper portion of each contact hole is then formed through the one or more upper layers of dielectric material. In order to properly align the upper portion of each contact hole with its corresponding plug, the dimensions across the bottom of the upper portion of each contact hole must be significantly smaller than the dimensions across the top of the conductive plug. If the dimensions of across the top surface of each conductive plug are too small, misalignment may occur and a contact formed in the upper portion of each contact hole may not communicate electrically or establish sufficient electrical communication with its corresponding conductive plug. If the dimensions across the bottom of the upper portion of each contact hole are too small, contact resistance between a contact formed therein and the conductive plug may be undesirably high.
Accordingly, there are needs for contact structures and contact fabrication processes that facilitate a continued decrease in the dimensions of features of semiconductor device structures.